Cold stress is a major abiotic stress that seriously hinders plant growth and development, ultimately affecting crop yields. During the process of evolution, plants have evolved sophisticated adaptive strategies encompassing acclimation processes and tolerance mechanisms. Over the past two decades, substantial research breakthroughs have been made in elucidating the core components and complex regulatory networks underlying cold tolerance. This review systematically synthesizes the recent progress in three fundamental aspects: cold stress perception and signal transduction pathways, downstream physiological and molecular responses, and the pivotal regulatory roles of transcription factors (particularly CBF/DREB1 family) and cold-responsive miRNAs. In addition, we also investigated the intricate crosstalk between cold response and other biological processes including photoperiod sensing, flowering regulation, circadian rhythm, phytohormone signaling, and the dedicated discussion addresses how plants achieve metabolic and developmental trade-offs when allocating resources between cold defense and other vital traits. Looking forward, we propose four promising research directions: identifying novel cryo-sensors beyond currently known receptors, post-translational modification dynamics of CBF proteins, homeostatic control mechanisms among competing regulatory factors, and translational applications of cold stress pathways in precision breeding programs. Addressing these knowledge gaps will not only deepen our understanding of plant cold adaptation at molecular level, but also facilitate the development of climate-resilient crops through molecular design breeding.

The two-component system (TCS), consisting of histidine kinases (HKs), histidine phosphotransfer proteins (HPs) and response regulators (RRs) in eukaryotes, plays pivotal roles in regulating plant growth, development, and responses to environment stimuli. However, the TCS genes were poorly characterized in rapeseed, which is an important tetraploid crop in Brassicaceae. In this work, a total of 182 BnaTCS genes were identified, including 43 HKs, 16 HPs, and 123 RRs, which was more than that in other crops due to segmental duplications during the process of polyploidization. It was significantly different in genetic diversity between the three subfamilies, and some members showed substantial genetic differentiation among the three rapeseed ecotypes. Several hormone- and stress-responsive cis-elements were identified in the putative promoter regions of BnaTCS genes. Furthermore, the expression of BnaTCS genes under abiotic stresses, exogenous phytohormone, and biotic stresses was analyzed, and numerous candidate stress-responsive genes were screened out. Meanwhile, using a natural population with 505 B. napus accessions, we explored the genetic effects of BnaTCS genes on salt tolerance by association mapping analysis and detected some significant association SNPs/genes. The result will help to further understand the functions of TCS genes in the developmental and stress tolerance improvement in B. napus.